In the state of the art, this function is for example carried out by a cam, or by an optical system decoding information contained on a disk fixed to the rotating part. On such a disk, at each angular position, is associated a coded information and the reading of this information directly provides the position of the part.
A drawback of the mechanical cam is that the reading of the position is purely mechanical and is accordingly not liable to be directly used by an electronic system. However, an electronic processing of information is necessary if one wishes to obtain sophisticated decisions and, for example, associate the information to other information provided by other measurement means.
The optical coded-areas measurement system presents the drawback to be expensive. The disk itself is not easy to make and the information reading necessitates sophisticated electronics. Generally, the information is coded by alternate transparent and dark areas on the disk and the reading thereof necessitates a directive light source and a reading means that is also directive. Such an implementation is not possible each time the rotative part is in a severe environment or when a cheap system is wished, or both.
An object of the instant invention is to provide for an electronic device for angular measurement providing a signal directly calibrated into angular values.
Another object of the invention is to provide for such a device using a very simple sensor.